1. Field of the Invention
This invention relates to the glass construction of an automobile, and more particularly, to an improvement of the glass construction when using two-dimensional glass.
2. Description of the Prior Art
Conventionally, two-directional curved glass which curves relative to a vertical direction is generally used in an automobile for the purpose of improving the aerodynamic characteristics and outward appearance of the automobile. Two-directional curved glass used for side doors, for example, which is set movably in a vertical direction, and in which guide rails, door sashes, etc. guide the glass in an upward-and-downward motion, is almost the same in structure as plane glass construction and in an upward-and-downward direction is movable in almost the same curvature as the curvature of glass.
The use of three-directional curved glass has recently been suggested for the front side doors which not only curves in up-and-down direction but also curves in a direction at a right angle to the up-and-down direction so that when the door glass is in a raised position (closed position), an upper part on a front edge side of the door glass is located more inwardly of a car body than an upper part on a rear edge side, thereby improving the aerodynamic characteristics and outward appearance of the automobile (refer to West-German Patent No. 3037397, etc.).
Three-directional curved glass involves higher manufacturing costs than plane glass and two-directional curved glass and requires the use of guide rails, door sashes, etc. of special construction due to the difference in shape between a front edge portion and a rear edge portion of the glass and other factors. Thus, it is feared that use of three-directional curved glass lacks reliability in respect of sealability and other points.